Abstract: The dual-power and dual-wire full penetration welding process for the NM400 wear-resistant steel plate used in scraper conveyor middle trough was studied. K-groove test plates were fabricated to study the penetration characteristic of the root pass, welding cold cracking sensitivity and mechanical properties of the butt joints, and the optimal dual-power and dual-wire welding process for K-shaped groove with large root face of the middle trough was determined. The penetration test of the root pass show that when the welding current is 360 A, the welding voltage is 36 V, and the welding speed is 40 cm/min, the full penetration welding of the 5 mm root face K-shaped groove is achieved by robotic single-wire welding. The cold cracking sensitivity test indicates that when the preheating temperature is 100 ℃, no cold cracks occur in the weld seam under relatively strict restraint conditions. The mechanical property test of the butt joint shows that when dual-power dual-wire welding is adopted for filling and capping passes: for the filling pass, the front wire current is 350 A, the rear wire current is 340 A, the front wire arc voltage is 32 V, the rear wire arc voltage is 31 V, and the welding speed is 60 cm/min. For the capping pass,the front wire current is 340 A, the rear wire current is 330 A, the front wire arc voltage is 31.5 V, the rear wire arc voltage is 30.5 V, and the welding speed is 50 cm/min, the tensile strength and impact toughness of the welded joint meet the service requirements. The surface of the bending test specimen shows no visible cracks, and the metallographic structure of the welded joint in all regions conforms to expectations.